1. Field of the Invention
This invention relates to harmonic tuning for multi-band radio receivers of the superheterodyne type and, more particularly, to a harmonic tuning system utilizing common control circuitry for rapid and accurate tuning to different radio frequency channels on the same and different broadcast bands.
2. Description of the Prior Art
Harmonic tuning systems have been known in the past for radio frequency apparatus such as television receivers, includng multi-band receivers. Such systems have been inherently one-way in tuning direction with minimal resolution. In particular, the prior art harmonic tuning systems have required the generation of harmonic signals at frequency spacings comparable to the frequency spacing between adjacent radio frequency channels and the use of intermediate frequencies less than the frequency difference between adjacent harmonic signals.